I like both Jigen and Lupin III equally, but I really like Jigen's character due to comedy and marksmanship. Lupin also introduces more comedy but I value his intelligence and brainpower a lot, since he comes up with stuff I would never have thought of. Zenigata is also one of my favorites since he's a pretty funny and wise character. He also has an awesome suit.

A lot of people like Jigen, and I see why. To be frank, I think all of them are great. Goemon and Jigen often bond well and it's wholesome, while also being good at making jokes and stuff. Lupin III especially interacts with them in a way that's humorous, though I often see Lupin III being the one that thinks a bit different specifically because of Fujiko and just well, being the butt of the joke sometimes.